[openmubr]

Summary

• In SkillCastSystem, avoids the +0.5 float range slack for Dark Side (263/559) and also checks integer-tile Chebyshev distance (Math.max(|~~tx - ~~heroPos.x|, |~~ty - ~~heroPos.z|) <= def.distance) so the client approaches instead of firing from a tile the server rejects (RageSkillAttackAction checks integer Chebyshev distance).
• In PointerInputSystem, resets pointerPressed and
  ightPointerPressed on window.blur and document.visibilitychange (when hidden) so a missed pointerup on Alt+Tab does not keep world.castRequest pinned.
• In mu_helper/loop.ts, switches away from a distant sticky currentTarget (>= 3 tiles) to an adjacent monster (<= 2 tiles) if it remains stuck for >= 3 seconds.
• Adds a unit test in skillCastSystem.test.ts verifying Dark Side's integer-tile boundary approach.